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710 results about "Pilot channel" patented technology

Pilot channel. [′pī·lət ‚chan·əl] (civil engineering) One of a series of cutoffs for converting a meandering stream into a straight channel of greater slope.

Interference suppression in a CDMA receiver

A system and method for canceling interference present in a code-division multiple access (CDMA) channel signal received at a CDMA receiver that is caused by multipath components of a transmitted pilot channel signal or by soft handoff conditions is computationally efficient because it operates at symbol rates. The channel signal from which such multipath interference is canceled can be either a traffic (data) channel or the pilot channel itself. Interference signals are produced in groups corresponding to the fingers of the CDMA rake receiver. The interference signals corresponding to each finger are used to cancel interference in the other fingers.
Owner:HMD GLOBAL

Power control apparatus and method in a wireless communication system using scheduled packet data service channel

Disclosed is a method for handing-off a mobile station receiving packet data over a second channel from a first base station system (BSS) to a second BSS by a base station controller (BSC) in a system in which the mobile station communicates with the first BSS and the second BSS adjacent to the first BSS through a first channel for transmitting a control message, and the mobile station communicates with the first BSS through the second channel for transmitting the packet data. In the method, the mobile station measures receiving strengths of pilot channels transmitted from the first BSS and the second BSS, and transmits the measured receiving strengths to the BSC through the first BSS and the second BSS. The first and second BSSs each calculate available transmission power allocable to the second channel and transmits the calculated available transmission power to the BSC. The BSC calculates a sum of the available transmission power and the measured receiving strength of the pilot channel from the first BSS and a sum of the available transmission power and the measured receiving strength of the pilot channel from the second BSS. The BSC transmits a handoff indication message to the second BSS, when the sum of the available transmission power and the measured receiving strength of the pilot channel from the second BSS is higher than the sum of the available transmission power and the measured receiving strength of the pilot channel from the first BSS.
Owner:SAMSUNG ELECTRONICS CO LTD

Adaptive power control in wideband CDMA cellular systems (WCDMA) and methods of operation

A WCDMA system includes a Base Station (BS) transmitter, or forward transmitter and a pilot channel that transmits control signals between the BS and a Mobile Station (MS) to reconfigure their transmitter / receiver. Reconfiguration is performed according to the prediction of the channel attenuation and the threshold set at the BS or MS based on its channel power probability density function separated into three distinct equal probable regions. In one embodiment, Seamless Rate Change (SRC) / Transmitter Power Control (TPC) logic uses the predicted channel attenuation to signal both the transmitter and the receiver in a channel to reconfigure their transmit power level according to the power density function (pdf) of the channel power and threshold level. A transmission rate is reduced when the power level is below the threshold and increased when the channel power is above threshold. The pilot channel is used to signal the mobile station and the base station.
Owner:IBM CORP

Adaptive power control based on a rake receiver configuration in wideband CDMA cellular systems (WCDMA) and methods of operation

A WCDMA system includes a Base Station (BS) or forward transmitter and a pilot channel that transmits control signals between a Mobile Station (MS) and BS to reconfigure their transmitter / receiver according to the prediction of the channel power and channel power probability density function separated into three distinct equal probable regions. Data signals are encoded using a one-half Viterbi encoder and interleaved. The interleaved data bits are modulated using Quadrature Phase Shift Keying (QPSK) modulation. The QPSK data is multiplexed with the pilot channel and spread by an appropriate code in an OFDM transmitter modified by a long code. Output of the transmitter may be provided to two diverse antennas for reliable communications to the receiver. Data may be received at two diverse antennas. The outputs are provided to match filters coupled to a coherent rake receiver and a channel prediction system. The future attenuation of the channel coefficients and power are determined by the prediction system for several milliseconds. The power levels of each finger in the Rake receiver can be predicted and the strongest ones used in determining the optimum transmitter power or rate control for operating the system transmitters and receivers based on computing a long range power prediction of each finger of a rake receiver.
Owner:WISTRON CORP

Balancing load of cells in inter-frequency handover of wireless communications

The present invention provides a method and an apparatus for allocating frequency bands associated with a multi-band network across a first and a second cell in a communications system. The method comprises determining a load parameter associated with the first and second cells in the communications system, selecting a target cell among the first and second cells for a mobile wireless device for transferring the mobile wireless device from a first frequency band to a second frequency band based on the load parameter of the first and second cells. In one embodiment, selection of an appropriate frequency band may be realized for a mobile wireless device in a multi-band network based on measurements of pilot channel properties and a load parameter to take into account a cell load of a target set of cells for an inter-frequency handover. This integration of the cell load for ranking, selection and transfer of user to a target cell from an overloaded cell may prevent unnecessary inter-frequency handover of users to cells with a relatively higher load, resulting in an increase in overall system capacity as well as quality of service.
Owner:LUCENT TECH INC

System and Method for Supporting Antenna Beamforming in a Cellular Network

ActiveUS20110065448A1Improved network bandwidth performanceReduce overhead transmissionPower managementSignal allocationBeam patternWide band
The present invention is a method and system for supporting a beamfonming antenna system in a mobile broadband communication network with an improved beam pattern, beam sweep pattern, pilot channel design with feedback and reporting rules, and control signaling design. Specifically, the improved beam pattern includes a method of supporting wireless communications in a wireless network forming at least two spatial beams within a cell segment where the at least two spatial beams are associated with different power levels, and separately, where at least two spatial beams can be moved across the cell segment according to a unique sweep pattern. The pilot channel design improves network bandwidth performance and improve user mobility tracking. Feedback and reporting rules can be established using a particular field designator, CQI, in the preferred embodiment.
Owner:APPLE INC

Geolocation of a mobile terminal in a CDMA communication system

A cellular radio system in which a base station receiver can receive, on the reverse link, data from a mobile terminal in one of four control modes. In the first mode, the mobile terminal sends an independent user pilot, not synchronized with the base station, on the reverse link and the user data channel is synchronized to this independent user pilot. In the second mode, the mobile terminal slaves its user pilot to the pilot it receives from the base station and the user data channel is synchronized with this slaved user pilot. This second mode allows the user terminal to receive round trip delay information for purposes of geolocation and rapid reacquisition. In the third mode, the mobile terminal slaves its user pilot to the incoming base station pilot, as in the case of mode two, but the user data channel operates in the orthogonal mode using the ranging information received from the base station. The phase relationship between the user pilot channel and the user data channel is calibrated. The user pilot carrier is also the carrier for the user data channel and can be used as the carrier reference for detecting the user data channel. In the fourth mode, the slaved pilot implementation of mode three is used for acquisition but, after acquisition, the user pilot code is phase shifted to be synchronous with the user data channel, thus also making it an orthogonal channel. In this mode, the pilots no longer contribute interference to the user data channels, within the cell, and can be transmitted at higher power levels.
Owner:INTERDIGITAL TECH CORP

Method and apparatus for associating with a communication system

A method in a wireless device (100) for communicating with a WLAN access point (112) and a wide area network is disclosed. The first step (302) includes scanning a first set of channels in a first radio frequency band for at least one pilot channel signal. In the next step (304) the device 100 receives a pilot channel signal on the first radio frequency band, the signal having a unique identification. The device, in response to receiving the pilot channel signal with the unique identification then turns on (306) a receiver that receives signals in a second radio frequency band. The device then searches, in step (308) for a signal, on the second radio frequency band, for a WLAN access point. The device then determines if a WLAN access point signal has been received, in step (310). The device associates with the WLAN, in step (312) if the device receives the WLAN access point signal. The device, in step (314), turns off the receiver if a WLAN access point signal has not been received.
Owner:MOTOROLA INC

Physical layer structures and initial access schemes in an unsynchronized communication network

Physical layer structures and related access schemes for unsynchronized communication networks are provided. Access channel information, preferably including a common synchronization code associated with all transceiver stations in a communication network and a cell-specific synchronization code uniquely associated with one of the transceiver stations, is modulated onto at least one set of time-continuous signal components of a communication signal. In order to access the communication network, communication terminals search for the access channel information in one or more sets of time-continuous signal components and synchronization parameters are then determined based on a location of the access channel information in the sets of time-continuous signal components. Some embodiments of the invention provide for joint frame synchronization and coarse timing synchronization. In further embodiments, the communication signal also includes a scattered pilot channel onto which a portion of the access channel information, preferably the cell-specific synchronization code, is modulated. The pilot channels may then be re-used for initial access operations in addition to its conventional uses for such operations as channel estimation.
Owner:APPLE INC

Mobile communication apparatus with multiple transmission and reception antennas and mobile communication method therefor

A mobile communication apparatus with multiple transmission and reception antennas and a mobile communication method therefor are provided. In the mobile communication apparatus including a base station and a mobile station, the base station with at least one transmission antenna restores long-term information, short-term information, a signal to interference and noise ratio (SINR) from a feedback signal received from the mobile station, spatially processes dedicated physical channel (DPCH) signals using basis information generated from the restored long-term information, short-term information, and SINR, and transmits the results of adding pilot channel (PICH) signals to the spatially processed results to the mobile station. The mobile station with at least one reception antenna determines a first characteristic corresponding to the channel downlink characteristic for each of the transmission and reception antennas, from the PICH signals transmitted from the base station, determines the long-term information, the short-term information, and downlink power control information including the SINR, which reflect the first characteristic, converts the determined long-term information, short-term information, and downlink power control information into the feedback signal, and transmits the feedback signal to the base station.
Owner:SAMSUNG ELECTRONICS CO LTD

AFC control apparatus and method in mobile communication system and mobile communication equipment using the apparatus and method

An AFC control apparatus in mobile communication equipment includes a depreading unit, first integrator, and control section. A despreading section despreads the reception signal. The first integrator integrates despread outputs obtained by despreading, of pilot symbols contained in a pilot channel of the reception signal, N (N is a number of 2 or more) consecutive first symbols and N second symbols succeeding the N first symbols, and generates first and second integral outputs. The control section detects any phase shift amount between the first and second integral outputs and controls the frequency of the local signal in accordance with the detected phase shift amount. An AFC control method and mobile communication equipment having the above apparatus and method are also disclosed.
Owner:NEC CORP

Incremental pilot insertion for channnel and interference estimation

Dynamic resource allocation systems, apparatus, and methods are disclosed for selectively improving the ability of a receiver to determine a channel estimate in an Orthogonal Frequency Division Multiple Access (OFDMA) system. A wireless communication system can use a common pilot channel configuration to aid channel estimation in one or more receivers in communication with the system. A receiver in communication with the system may be unable to demodulate received data due to an inaccurate channel estimate. The receiver can communicate to a transmitter in the system a request for additional channel estimation resources. The wireless communication system can provide additional channel estimation resources by inserting dedicated pilot channels into one or more of the frequencies allocated to symbols for the receiver. If the receiver is still unable to demodulate received data, the wireless communication system can incrementally insert additional pilot channels in the symbol associated with the receiver.
Owner:QUALCOMM INC

Method and apparatus for hybrid CDM OFDMA wireless transmission

A method and apparatus for wireless transmission from a mobile unit to a base station includes multiplexing a pilot signal and a data signal, wherein the data signal operates at a data rate by splitting the data signal into a plurality of data streams; applying a pilot gain to the pilot channel, wherein the data gain and the pilot gain are a function of the data rate; and combining the plurality of data streams and the pilot signal into a subset of sub-carriers. The subset of sub-carriers are transmitted using Discrete Fourier Transform Spread OFDMA.
Owner:GOOGLE TECHNOLOGY HOLDINGS LLC

Soft combining apparatus and method in a CDMA mobile communication system providing MBMS service

A method and apparatus for determining soft handover in a CDMA mobile communication system supporting Multimedia Broadcast / Multicast Service (MBMS) is provided. In the asynchronous CDMA mobile communication system supporting MBMS, when a UE moves to a region where it can receive data from a plurality of Node Bs, the UE determines whether to perform soft combining using a measurement value of a dedicated pilot channel signal, in performing soft handover. In this way, the UE can determine whether to perform soft combining on MBMS data received from a plurality of Node Bs by itself. Therefore, even though an MBMS user moves from a current or existing cell to a new cell, a stable MBMS service is provided to the user, thereby contributing to the user's convenience.
Owner:SAMSUNG ELECTRONICS CO LTD

Method and apparatus for controlling transmission and reception of dedicated pilots according to MCS level in a wireless communication system

A method and apparatus for controlling transmission and reception of dedicated pilots according to an MCS level in a wireless communication system are provided, in which an MCS level is determined for a data channel, the amount of resources for sending dedicated pilots is determined in inverse proportion to the MCS level, a pilot channel signal including basic pilots mapped to resources allocated to a pilot channel, a control channel signal including control information mapped to resources allocated to a control channel, and a data channel signal including the dedicated pilots mapped to the determined amount of resources being part of resources allocated to the data channel and data mapped to the remaining of the resources allocated to the data channel are generated, and the pilot channel signal, the control channel signal, and the data channel signal are multiplexed and sent in the mapped resources.
Owner:SAMSUNG ELECTRONICS CO LTD

Enhanced channel estimator, method of enhanced channel estimating and an OFDM receiver employing the same

The present invention provides an enhanced channel estimator for use with an orthogonal frequency division multiplex (OFDM) receiver employing scattered pilot channel estimates. In one embodiment, the enhanced channel estimator includes a time interpolation estimator configured to provide time-interpolation channel estimates having at least one image for a portion of carriers having the scattered pilot channel estimates. The enhanced channel estimator also includes a frequency interpolation estimator coupled to the time interpolation estimator and configured to provide frequency-interpolation channel estimates for each carrier based on image suppression through balanced-error filtering.
Owner:TEXAS INSTR INC

Transmitting/receiving apparatus and method for cell search in a broadband wireless communications system

Disclosed is transmitting / receiving apparatus and method for efficient cell search in a broadband wireless communication system using multiple carriers. The apparatus includes a BS generating an SCH signal by mapping predetermined symbols to predetermined subcarriers according to a code group to which the BS belongs, code-multiplexing a TCH signal and a pilot channel signal mapped to a predetermined time-frequency area and scrambling the code-multiplexed signal with a predetermined scrambling code identifying the BS along a time axis first, time-multiplexing the SCH signal with the scrambled signal, OFDM-modulating the time-multiplexed signal, and transmitting the OFDM-modulated signal.
Owner:SAMSUNG ELECTRONICS CO LTD +1

Transmission/Reception apparatus and method in a mobile communication system

Disclosed is a transmission / reception apparatus and method for providing compatibility between Code Division Multiple Access (CDMA) and Orthogonal Frequency Division Multiplexing (OFDM) in a forward link. The proposed transmission / reception apparatus and method uses a traffic channel based on OFDM while using a pilot channel and a sync channel used in the CDMA scheme. Thus, a transmitter adds a pilot channel signal and a sync channel signal to OFDM-modulated symbols before transmission, and a receiver acquires a pilot channel signal and a sync channel signal, and removes them from a received signal, thereby outputting only pure OFDM-modulated symbols.
Owner:SAMSUNG ELECTRONICS CO LTD

CDMA cellular radio transmission system

A base station transmits, in addition to a pilot channel, signals which are multiplexed with pilot symbols inserted in the respective signals in communication channels. As the transmission of the pilot channel as a reference signal for coherent detection is unnecessary with high power so as to attain high reliability, the pilot channel can be transmitted with low power by means of weight in comparison with the communication channel, so that interference with the communication channel of any other station is reduced. Moreover, accurate coherent detection can be made from the pilot symbol inserted in the communication channel on the mobile station side.
Owner:PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

Transmission apparatus and reception apparatus

A transmission apparatus used in a mobile communication system adopting a single carrier scheme in an uplink includes: multiplexing means configured to multiplex a pilot channel, a control channel, and a data channel; and transmission means configured to transmit a transmission symbol including at least the pilot channel and the control channel using the uplink. A first pilot channel used for a reception apparatus to measure channel state of the uplink is transmitted using a frequency band over a plurality of resource blocks. A second pilot channel for compensating for a channel transmitted by the uplink is transmitted by a resource block assigned to the transmission apparatus. Control channels of the transmission apparatus and the apparatus other than the transmission apparatus are orthogonalized with each other by a FDM scheme.
Owner:NTT DOCOMO INC

Soft combining apparatus and method in a CDMA mobile communication system providing MBMS service

A method and apparatus for determining soft handover in a CDMA mobile communication system supporting Multimedia Broadcast / Multicast Service (MBMS) is provided. In the asynchronous CDMA mobile communication system supporting MBMS, when a UE moves to a region where it can receive data from a plurality of Node Bs, the UE determines whether to perform soft combining using a measurement value of a dedicated pilot channel signal, in performing soft handover. In this way, the UE can determine whether to perform soft combining on MBMS data received from a plurality of Node Bs by itself. Therefore, even though an MBMS user moves from a current or existing cell to a new cell, a stable MBMS service is provided to the user, thereby contributing to the user's convenience.
Owner:SAMSUNG ELECTRONICS CO LTD

Method and apparatus for providing an efficient pilot scheme for channel estimation

An approach for utilizing a pilot scheme in a spread spectrum communication system (e.g., Multi Carrier Code Division Multiple Access (MC-CDMA)) is provided. A communications link includes a sub-bands and a single pilot channel that is designated for the sub-bands for channel estimation. Pilot symbols transmitted over the single pilot channel are used to determine a first channel estimate associated with a first one of the sub-bands, and a second channel estimate corresponding to a second one of the sub-bands is derived from the first channel estimate.
Owner:NOKIA CORP

Transmitting and receiving apparatuses and methods

A transmitting apparatus which transmits a transmit symbol in orthogonal-frequency division multiplexing (OFDM) is disclosed. The transmitting apparatus includes a unit which provides a unicast channel; a unit which provides a multimedia broadcast multicast service (MBMS) channel; a unit which provides a specific pilot channel which is specific to a specified cell; a unit which provides one or more common pilot channels common to a plurality of cells; and a multiplexing unit which multiplexes the unicast channel, the MBMS channel, the specific pilot channel, and the one or more common pilot channels, and creates the transmit symbol, wherein the multiplexing unit time-division multiplexes, in the same frequency band, a unicast frame which includes the unicast channel, and an MBMS frame which includes the MBMS channel, and wherein an insertion density of the common pilot channel included in the MBMS frame is larger than an insertion density of the specific pilot channel included in the unicast frame.
Owner:NTT DOCOMO INC

Wireless communication method, base station and, wireless communication system

Data transmission is performed using the most suitable data rate for the radiation pattern of an antenna. Using an individual pilot channel of a first slot, a base station transmits a pilot signal in a specified direction with a beam pattern having narrow directivity. A wireless terminal located in that direction receives the pilot signal and determines a data rate according to the reception quality of the pilot signal. The wireless terminal transmits to the base station a signal requesting the determined data rate. The base station receives that signal and, based on the requested data rate, transmits data to the wireless terminal with a beam pattern in the same direction as the direction in which the pilot signal was transmitted, using a data channel of a second slot, which occurs a predetermined number of slots after the first slot.
Owner:HITACHI LTD

Method and arrangement for transmitting cq1 on the uplink

A method for transmitting data flows between a network element and a number of receivers over a first channel. The method comprises the steps of: performing a link adaptation for the transmission of a data flow by said network element, and transmitting the data flow, transmitting an indication of a channel quality required for reception of the data flow on a second channel, receiving by said receivers said indication of channel quality, measuring a link quality by said receivers by monitoring a pilot channel, comparing said measured link quality with said received indication of the channel quality, and transmitting to said network element result of said comparison of said measured link quality with said received indication of the channel quality, if said result is lower than a predetermined value. The invention also relates to a network element and a user equipment.
Owner:GUANGDONG OPPO MOBILE TELECOMM CORP LTD

Adaptive downlink packet transmission method in multicarrier CDMA system

Disclosed is an adaptive downlink packet transmission method for a multicarrier Code Division Multiple Access (MC-CDMA) system. The method can allocate radio resources efficiently according to the variations of channel conditions for each user terminal, allocate transmission power appropriately according to the interference from the same cell, and minimize interference to adjacent cells. The adaptive downlink packet transmission method includes the steps of: a) estimating a signal-to-interference-and-noise ratio (SINR) in a user terminal after channel equalization and despreading by measuring a downlink pilot channel; b) measuring an average interference factor and an average noise power; and c) allocating radio resources adaptively in the central station by determining transmission slots in a transmission frame, the number of spreading codes to be used in each transmission slot, symbol energy for each spreading code, and a transmission method, until transmission slots and packets to be allocated are not available.
Owner:ELECTRONICS & TELECOMM RES INST

TDD system based cell handoff method and user equipment

The present invention discloses a cell handoff method and a user equipment based on a TDD system. The method includes: step A. a UE measures received pilot channels of a source cell and a neighboring cell according to a measurement control message and reports measurement result to a RNC; step B. the RNC, determines whether a target cell to be subject to a cell handoff process has available resources at a time slot different from that of the source cell and if yes, transmits a cell handoff command to the UE, allocates available resources for the UE in the target cell and transmits traffic carrier data of the UE to the source cell and the target cell respectively; and step C. after receiving the cell handoff command, the UE communicates with the source cell and the target cell at a same frame and at same time according to the allocated available resources. According to the handoff method of the present invention, UE can more reliably receive the handoff control command transmitted by the RNC and during the handoff process, the transmission power and interference are reduced so that the reliable handoff of a UE is guaranteed and the system performance is improved.
Owner:SHANGHAI ULTIMATE POWER COMM TECH

Adaptive transmit antenna diversity apparatus and method in a mobile communication system

Apparatus and method are disclosed for selecting a transmit antenna diversity scheme according to a variation speed of a fading channel in a mobile communication system. A user equipment (UE) estimates a channel response of a pilot channel by receiving a pilot channel signal from a Node B; estimates a variation speed of a fading channel by using the estimated channel response and determining a transmit antenna diversity scheme suitable to the variation speed of the fading channel; and transmits feedback information including the determined transmit antenna diversity scheme to the Node B, so that the Node B can determine a transmit antenna diversity scheme for a channel signal to be transmitted to the UE based on the transmit antenna diversity scheme information included in the feedback information. In this way, the Node B adaptively applies a transmit antenna diversity according to a channel condition.
Owner:SAMSUNG ELECTRONICS CO LTD

Apparatus and method for transmitting/receiving feedback information in a mobile communication system using array antennas

Provided is a method for transmitting feedback information by a receiver in a mobile communication system that performs multiplexing transmission using array antennas. The method includes determining a weight set for maximizing a data rate among at least one weight set having, as its elements, multiple orthonormal weight vectors, based on a fading channel estimated from a pilot channel of received data; estimating channel state information corresponding to a weight vector of the determined weight set; and generating and transmitting feedback information including an index of the determined weight set, the selected weight vector information, and the channel state information corresponding to the weight vector.
Owner:SAMSUNG ELECTRONICS CO LTD
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